A new technique to determine organic and inorganic acid contamination

Abstract

A new acid indicator pad was developed for the detection of acid breakthrough of gloves and chemical protective clothing. The pad carries a reagent which responds to acid contaminant by producing a color change. The pad was used to detect both organic and inorganic acids permeating through glove materials using the modified ASTM F-739 and direct permeability testing procedures. Breakthrough times for each type of glove were determined, and found to range from 4 min to >4 h for propionic acid, from 3 min to >4 h for acrylic acid, and from 26 min to >4 h for HCl. A quantification was performed for propionic and acrylic acids following solvent desorption and gas chromatography. Both acids exhibited >99% adsorption {the acid and its reactivity (the acid reacted with an indicator to contribute the color change)} on the pads at a spiking level of 1.8 μL for each acid. Acid recovery during quantification was calculated for each acid, ranging from 52–72% (RSD ⩽ 4.0%) for both acids over the spiking range 0.2–1.8 μL. The quantitative mass of the acids on the pads at the time of breakthrough detection ranged from 260–282 and 270–296 μg cm⁻² for propionic acid and acrylic acid, respectively. The new colorimetric indicator pad should be useful in detecting and collecting acid permeation samples through gloves and chemical protective clothing in both laboratory and field studies, for quantitative analysis.